1. Technical Field
Systems and methods are disclosed for lubricating a transport system, in particular an escalator or a moving walk. The disclosed systems are driven kinematically by a rotating shaft of the transport system and converting the relatively fast rotational motion of the shaft to a slow linear motion for delivering lubricant over prolonged dispense cycles. As a result, the disclosed systems and methods use substantially less lubricant than conventional systems.
2. Description of the Related Art
An escalator includes a plurality of steps that are connected together by one or more circulating step chains forming an endless loop. The escalator steps are arranged to be able to be vertically offset relative to each other along certain portions of the endless loop to create a vertical rise. In contrast, a moving walk includes a plurality of pallets that are joined together by one or more circulating pallet chains for the horizontal transportation. In both transport systems, handrails can be provided that are driven via handrail chains. Step chains, pallet chains and handrail chains are typically coupled to one or more drive units by sheaves or sprockets driven by an electric motor.
To reduce friction and power requirements and to increase the service life of the transport system, the step, pallet and handrail chains should be lubricated at regular intervals. Additionally, escalator and moving walk systems also include parts that require regular lubrication such as bearings, other chains, ropes, etc. Preferably, the lubrication is performed automatically.
Currently available automatic lubrication systems include: “drip-feed” systems or gravity fed systems that supply lubricant intermittently in the form of droplets applied directly to parts needing lubrication; “oil-mist” or injection spray systems that spray or inject lubricant on parts needing lubrication; and continuous feed systems that deliver lubricant in the form of a stream to parts needing lubrication. Each of these lubricating systems have inherent disadvantages.
One common disadvantage is inefficient use of lubricant or wasted lubricant. Because most lubricants are derived from non-renewable petroleum sources, wasted lubricant is becoming a greater concern as companies are being encouraged to reduce their use of fossil fuels, reduce their carbon footprint and conduct themselves in environmentally sensitive ways. Further, wasted lubricant must also be safely disposed of, which may be problematic for the maintenance crew of the transport system or the building owner if a recycling facility is not readily accessible.
Returning to the disadvantages of currently available lubricating systems, drip-feed systems suffer from difficulties in terms of timing the droplet discharge from the nozzle with the link points of each chain link joint. The flow of lubricant typically cannot be easily moderated with drip-feed systems, which means that lubrication also takes place when the escalator or moving walk is stationary thereby resulting in waste. Drip-feed systems also cannot respond adequately to environmental conditions that require different quantities of lubricant. Furthermore, different lubrication requirements of different lubrication points cannot normally be accommodated with drip-feed systems.
Oil-mist or injection-spray type systems disperse lubricant on areas that do not need lubricant, thereby contaminating the surroundings and wasting lubricant. The continuous oil feed systems discharge lubricant at too high of a rate thereby also contaminating the surroundings and wasting lubricant in a manner similar to “oil-mist” lubrication systems. As a counter-measure to the excessive lubrication, an oil pan can be disposed below the power transmission train. However, oil pans must be drained thereby requiring additional labor and maintenance expenses and oil pans obviously do not solve the lubricant waste problem. While operators can be employed to lubricate transportation chains manually, such procedures are costly and expose the operators to unnecessary dangers.
Therefore, a need exists for improved lubricant delivery systems for transport systems such as escalators and moving walks which can more efficiently deliver needed quantities of lubricant than currently available systems.